Background: Multiple immunoglobulin E (IgE) mediated sensitizations and/or allergies often coexist in patients with allergic rhinitis (AR). Several simultaneous allergen exposures in multiple IgE-mediated sensitizations and/or allergies may increase the allergen load and be related to disease severity. No study has verified whether positive allergen serum IgE levels and allergen categories together are associated with AR severity in adults. Objective: To investigate the effects of perennial dust mites (DMs) allergy and multiple serum sIgE-mediated autumn pollen allergy coexistence on symptom severity in adult patients with AR in autumn. Methods: In total, 153 patients with AR and with autumn pollen allergy (Artemisia argyi, ragweed, and hop) with or without DMs allergy were recruited in the autumn pollen season. Symptom severity was assessed by using the Chinese version of the visual analog scale (VAS): four rhinitis symptoms (sneezing, rhinorrhea, nasal pruritus, and nasal congestion) and two ocular symptoms (ocular itching and/or grittiness and/or redness, and ocular tearing) were scored at approximately the same period. We measured allergen serum sIgE levels for the inhaled allergens. The effects of DMs allergy and multiple autumn pollen allergy coexistence on symptom severity were analyzed. Results: Neither the sum of the autumn pollen allergens categories (total number of positive autumn pollen allergens, i.e., Artemisia argyi or ragweed or hop positive: 1; Artemisia argyi and ragweed positive: 2; Artemisia argyi, ragweed, and hop positive: 3) nor serum sIgE levels( total sIgE levels of positive autumn pollen allergens) exerted any influence on the severity of nasal and ocular symptoms (p > 0.05). When the concomitant DMs allergy status was considered, the sum of the positive autumn pollen allergen categories and accumulated positive autumn pollen and DMs serum sIgE levels (total levels of serum sIgE of positive autumn pollen allergens plus the levels of serum sIgE of DMs) had no influence on patients' symptom severity (p > 0.05). Conclusion: The coexistence of perennial DMs allergy and multiple autumn pollen allergy did not affect the severity of symptoms among adult patients with AR and with autumn pollen allergy in autumn.